Mental retardation autosomal dominant 35 caused by de novo missense variants in PPP2R5D gene: a case report and literature review / 中华神经科杂志

ABSTRACT

Objective:To enhance understanding of mental retardation autosomal dominant 35 (MRD35) by analyzing the clinical and genetic characteristics of the disease.Methods:Clinical and genetic data of 1 case of MRD35 in Beijing Children′s Hospital in July 2018 were reported, and literature review was conducted.Results:The male proband, 1 year and 3 months old, was admitted with the clinical manifestations including mental retardation, low-grade fever, a large forehead, flat nose, open mouth, and hypomyotonia. The brain magnetic resonance imaging showed enlarged lateral ventricles, cavum septum, cavum verge and cavum velum interpositum cyst. The whole exome sequencing test showed that the proband carried a missense mutation c.1258 G>A, (p.E420K) in the PPP2R5D gene, and the mutation was de novo confirmed by Sanger sequencing. There were ten literatures reported, including a total number of 31 cases. Counting on this case, totally 32 cases were included. Among the 32 patients, 32 cases (100.0%) had mental retardation, 26 cases (81.3%) with motor retardation, 26 cases (81.3%) with macrocephaly, 8 cases (25.0%) with epilepsy. Facial dysmorphic features, ocular abnormalities, skeletal abnormalities, and cardiac malformations were also reported. All reported individuals had missense mutations of PPP2R5D gene and were autosomal dominantly inherited. Conclusions:The main clinical manifestations of MRD35 include growth retardation/mental retardation, severe speech impairment, macrocephaly, hypomyotonia, seizures and dysmorphic facial features. A novel missense mutation in the PPP2R5D gene is the cause of MRD35.